| 摘要 |
PROBLEM TO BE SOLVED: To provide a terminal control system for an automatic metering system that discriminates presence of channel connection even when a low line voltage terminal adaptor is connected to the system, attains terminal transmission, recognizes a call from a supervisory center and makes communication. SOLUTION: This terminal control system consists of a line current monitor section 3 that monitors a current at the time of acquiring a telephone line 25 and to which a terminal 26 is connectable, a line voltage monitor section 6 that is connected to a line voltage rectifier section 5 rectifying and converting a line voltage and discriminates presence of a voltage by using a prescribed threshold value, a call signal monitor section 4 that monitors the presence of an external call signal, a network control section 7 that controls line such as acquisition or open of the telephone line 25 and is connected to a selection signal transmission section 8 sending a selection signal after the acquisition of the telephone line 25 and to a data transmission reception section 9 sending/receiving data to/from a supervisory center, a meter interface section 13 that make communication with a meter 28 connected to a terminal controller 1, and a control section 2. The control section 2 discriminates a non-use state of the telephone line 25 by two state inputs of detection signals from the line current monitor section 3 and the line voltage monitor section 6.
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